To perform neurosurgery, it is typically necessary to advance a neurosurgical instrument, e.g., an endoscope, scalpel, etc. into the brain of a patient. The instrument is advanced into the brain until the operable portion of the instrument is positioned adjacent the site of interest, i.e., the site of the brain to be operated on. Then, the instrument is manipulated as appropriate for performing the particular procedure.
Modern neurosurgery techniques fall into two general categories. The first is relatively invasive and involves removing a large portion of the patient's skull, to gain access to the brain. After surgery, the portion of the skull which was removed is replaced.
The second type of neurosurgery, referred to herein as neuroendoscopy because it often permits advancing an endoscope into the brain to provide the surgeon with a view of the brain, is much less traumatic to the patient than the first. Neuroendoscopy requires drilling a small hole in the skull, and then advancing one or more surgical instruments and/or endoscopes through the hole into the brain to perform the operation. Neuroendoscopy is preferred when use of it is practicable, for the reason that it causes relatively little trauma to the patient and allows for relatively rapid patient recovery.
Not surprisingly, in neuroendoscopy the surgical instrument or instruments must be advanced along a precisely determined path into the brain, to avoid unintentionally damaging the brain. Also, once precisely positioned in the brain, the instruments must be securely held in position, again to avoid unintentional injury to the brain.
To aid the surgeon in advancing an instrument or probe along a precisely predetermined path, devices referred to as stereotactic frames have been introduced. A stereotactic frame can be positioned near the patient's skull prior to surgery, and the frame has one or more surgical instrument holders, each of which can securely grip a surgical instrument or probe and hold the probe in a predetermined orientation relative to the brain.
One type of stereotactic device is the Bookler Laparascopic Scope Holder made by Flex-Bar Machinery Corporation of New York. The Bookler Scope Holder has a flexible arm that has a fixed end which is mounted on a frame. The flexible arm, sometimes referred to as a gooseneck, has a free end, and the free end can be moved in any direction in three dimensional space relative to the frame, and can be locked relative to the frame once the free end has been placed in the desired position and orientation relative to the frame.
A neurosurgery instrument holder is connected to the free end of the gooseneck, such that a neurosurgery instrument can be engaged with the holder of the gooseneck. The instrument can thus be oriented relative to the frame as desired. To orient the instrument relative to the frame, the free end is unlocked, the instrument moved as desired, and the free end locked again in position.
It can be appreciated in reference to the above discussion that once a neurosurgery instrument has been engaged with the holder of the gooseneck and oriented as desired, the free end of the gooseneck must be unlocked to permit advancing the instrument along the predetermined path. Unlocking the free end, however, as discussed above, permits movement of the instrument in all three spatial dimensions.
This is undesirable, because it results in difficulty in simply advancing the instrument axially into the brain, while maintaining the orientation of the instrument relative to the brain. Stated differently, each time it is desired to move the instrument axially into the brain along the predetermined path, the free end of the gooseneck must be unlocked, permitting unintentional movement of the instrument in the remaining two dimensions and potentially causing the instrument to deviate from the predetermined path of advancement.
Accordingly, it is an object of the present invention to provide a device for permitting movement, in only a single direction, of a surgical instrument that is held by a surgical apparatus. Another object of the present invention is to provide an adaptor for engaging the holder of the flexible arm of a surgical apparatus and for selectively gripping a surgical instrument. Another object of the present invention is to provide an adaptor for connecting a surgical instrument to a surgical apparatus, that is easy to use and cost-effective to manufacture.